Microfluidic cell fusion under continuous direct current voltage

Cell fusion is a powerful tool for analysis of gene ex- pression, chromosomal mapping, antibody production, clon- ing mammals, and cancer immunotherapy. Cell fusion has been carried out based on several approaches. Chemical and virus-mediated fusion methods were developed in the earlier years based on the application of chemical fusogens such as polyethylene glycol or fusogenic virus i.e., Sendai. 1,2 These methods have been associated with limitations such as tox- icity to cells, batch-to-batch variability, and low efficiency. In comparison, electrofusion, which is based on the applica- tion of high-voltage electric pulses, can be applied to a wide range of cell types with high efficiency and high postfusion viability. 3,4 Electrofusion typically requires specialized equipment which generates both low-voltage alternating cur- rent ac for cell alignment/contact and high-voltage direct current dc pulses for cell fusion. 5 Due to the complexity and cost associated with the instrumentation, very few stud- ies have explored realizing this important technique on a microfluidic platform. 6,7 All these demonstrations involved